Nitric Acid → 3,5-Dimethyl-4-nitropyrazole

Participants

Reaction Steps

To a solution of 3,5-dimethylpyrazole (86.5 g, 0.90 mol) in concentrated sulfuric acid (170 ml), conc nitric acid (103 ml, d=1.423) was added with stirring and icecooling. After one hour concentrated sulfuric acid (100 ml) was added slowly with stirring resulting in a temperature rise to 70°-80° C. After stirring overnight at 30°-35° C., the mixture was poured into ice (1.5 l) and neutralized with potassium hydroxide. Extraction with methylene chloride (3×350 ml), drying of the organic phase (Na2SO4) and evaporation gave off-white crystals which were dried in vacuo at 70°. Yield 106.2 g=83.6%, m.p. 125°.

Provenance & Evidence